This invention relates to the preparation and storage of food and other materials of a commercial and industrial nature such as cosmetics, pharmaceuticals and other organic and inorganic materials, and in particular to a device for rapidly cooling and heating food.
In the food preparation industry, the rapid cooling or heating of food is very critical. For example, when a large batch of food is prepared, for example, a stew, beans or the like, health food regulations, and safety requires the food to be cooled within a certain time period from the cooking temperature, (perhaps 140-165xc2x0 F.) to the storage temperature of 40xc2x0 F. The longer the food takes to cool, the longer the food will be at a temperature range conducive to the growth of harmful bacteria and the like which can spoil the food and cause illness.
The commercial food industry, for example, will often use manual labor to take large volumes of hot food and place them in plastic bags for protection and submerge the bags and food in ice baths to cool the food from the cooking temperature to the storage temperature. This is a very costly procedure given the energy and labor input that is required each time the procedure is undertaken. In addition, the bags are used to subsequently reheat the food. This process of using bags involves physically handling the food at each bag iteration. It often takes more than a four hour period to cool the food from the cooking temperature to the storage temperature. In addition to the bags and the ice baths, quite often the food is broken down into smaller pans to facilitate cooling. Again, this results in a waste of labor, energy and food and results in an increased possibility of cross-contamination. Many jurisdictions have regulations that limit the time for this cooling procedure and this must be monitored continuously.
In heating the food just before serving, time is also critical. It is desirable to keep this time as short as possible to give the preparer greater flexibility in the timing of the final meal service. Further, the shorter the interval of time to heat the food, the less time the food will be exposed to a temperature range conducive to the growth of bacteria. Also, less energy is required to heat the product to temperature and less product is lost to burning or dehydration at the edges nearest the heat source due to non-uniform heating of the product.
A need exists for a process to more rapidly heat and cool food to provide the advantages of a safer food service and to satisfy the applicable regulations, reduce energy, labor and product loss due to inefficient thermal effects.
In accordance with one aspect of the present invention, an apparatus is provided for rapidly changing the temperature of a mass of product. The apparatus includes at least one input heat transfer element extending into the mass of product and at least one output heat transfer element exposed to an ambient temperature environment to transfer thermal energy between the input heat transfer element and the output heat transfer element.
In accordance with another aspect of the present invention, the apparatus is employed with a pan containing the mass of product. A lid is provided for the pan which has a plurality of slots therein. The apparatus includes a plurality of input heat transfer elements formed as fins, the fins extending through the slots in the lid and into the mass of product therein. The output heat transfer element is positioned exterior the lid. In accordance with another aspect of the present invention, the fins can be removable. The fins also can touch the bottom of the pan to enhance heat transfer.
The input heat transfer elements can extend from the top of the pan down, from the bottom of the pan upward, or horizontally from the sides.
The apparatus may be integral with the top closure of the pan or may be used with an expandable handle to facilitate removal of the apparatus from the pan.
Heat transfer can occur by conduction, convection and radiation.
A working heat transfer medium, either a solid, liquid or gas, can be utilized to improve the heat transfer.